Re: iOS loses WiFi when sleeping

said by not :

...Like I said above. The requirements for WIFI sync to iTunes, etc. all require that you're plugged into power. When an iPhone is plugged into power, WIFI remains on when the phone gets locked and goes into Sleep. When unplugged from power and locked/Sleep mode, WIFI gets turned off and it's back to cellular only connectivity until you wake it up, at which point it reconnects to known WIFI networks in range that it's been connected to before...

Except mine was sleeping while plugged in and always lost WiFi connectivity, so...

OK ya you're wrong. When you wake the device and it's displaying a Cellular data symbol it was connected to a cellular data network plain & simple. When on a wi-fi network the iDevice should stay on that network until the signal degrades to the point of dropping the signal and switching to a stronger wi-fi signal or cellular data signal.

No I'm not wrong. When the device is in Sleep mode AND NOT PLUGGED IN, it'll drop off WIFI and back to 3G or whatever other cellular signal you're connected to. It's like this by design.

Yes you are most definitely wrong iPhones, and dare I say all smartphones have always been designed to stay on a known Wi-Fi signal. Reasons being Wi-Fi for the most part is historically faster than cellular data (unless one has LTE), and has a stronger more reliable signal causing significantly less battery drain because the cellular radio is not constantly trying to connect to a more distant cell tower, so as you can see it makes absolutely no sense for the phone to constantly be switching between Wi-Fi and cellular data unless there was an issue with the Wi-Fi connection. This seemed to be the problem the OP was having, so the first step in trouble shooting a Wi-Fi issue would be to "flush" the old connection from the system and establish a new connection between the device and the network. The OP then preformed this procedure achieving the desired results of not switching between the two data formats on two iDevices thus becoming happy with their now properly preforming devices, and proving my point at the same time.--Not many people know this, but I happen to be quite famous...

Nope. WIFI on an iPhone when active actually uses more power than cellular. Also, when WIFI is On on the iPhone, it doesn't shut cellular off. Where did you get that idea? What do you think it uses for calls and text message that aren't data based (i.e. iMessage)? It remain connected to both cellular and WIFI when WIFI is used. An iPhone actually never turns cellular off to save power.

Also, go read the Apple requirements for WIFI Sync to iTunes. It requires the device to be connected to power and be attached to a WIFI network. The reason being is that it requires that power plug to be connected in order to keep WIFI on. Sure, you can trigger a manual WIFI sync without power connected to it, but that's because when the device is away, it'll connect to WIFI due to the user actually using it. Being connected to power is the only thing that'll keep an iPhone from dropping off WIFI to save power. Plain and simple.

Annnd that's why back in the day before the advancement of cell phone batteries a popular trick to save battery life was to turn off the 3G data when not in use. 3G connections use a lot more battery than WiFi and 4G uses even more, when sending packets. Through WiFi, it only takes a few milliWatts to reach the wifi access point, but a 3G tower may be miles away, requiring a much stronger transmission signal.--Not many people know this, but I happen to be quite famous...

Annnd that's why back in the day before the advancement of cell phone batteries a popular trick to save battery life was to turn off the 3G data when not in use. 3G connections use a lot more battery than WiFi and 4G uses even more, when sending packets. Through WiFi, it only takes a few milliWatts to reach the wifi access point, but a 3G tower may be miles away, requiring a much stronger transmission signal.

A lot of that had to with chipset design and power management as well. It's not all about tower distance and radio power output. Fact is, the iPhone needs to maintain the same level of cellular connectivity regardless of the availability of WIFI or not. If it switched everything over to WIFI, you wouldn't get any calls. Besides, the push triggers for notifications and emails aren't that large. Take a quick peek at just how much of an email gets sent down to the phone on Push before you wake it up and WIFI gets triggered. When after that point you go into email, the rest of the email's data for full HTML and attachments come down.

If you don't believe me, then try this test. Unplug your modem but leave your router online. Your iPhone will bind to WIFI and be unable to send/receive data and it won't know any better because once WIFI is bound on the iPhone's TCP protocol layer, it's not been written in such a way as to see no Internet gateway availability and flip back to cellular data. Once it sleeps and WIFI goes inactive on just battery power, it'll start getting data pushed to it again for iMessages or emails, etc. Then when you wake it and if you have a large email, you'll notice that it's flipped back to WIFI but it won't have the full email downloaded, just TEXT based only and attachments will be in a "tap to download" state. If your WIFI was truly in a working state, that wouldn't be the case and it would quickly pull down the remainder of the email as you open the email program.

Ok you are arguing for the sake of arguing. Not once did I say anything about completely shutting cellular voice off, you are putting words into my mouth. No I don't believe you because I know better. There's no need to preform your complicated hokie test when all that needs to be done is to open your routers menu, and view which wireless clients are attached to your network. Mine shows my wife's iPhone, my iPhone, and my iPad with all three unplugged & sleeping. If one device leaves the house once out of range it switches to cellular data, and then drops off my wireless networks map ... we're done here, have a nice day.--Not many people know this, but I happen to be quite famous...

Sorry, but you're not correct. I looked at my router just now as well and while I can see the MAC of my iPhone is listed under attached devices, the IP and NAME of the device is NOT propagated, which means that it's not on a nail up connection. Yes, it is in a WIFI available sleep state, but WIFI is not 100% on. Also, I can wake it by pressing the Home button and see that the signal is on 3G and then almost immediately flips to WIFI even if I don't unlock it. You're just too hard headed to listen and realize what the truth is. And no, I'm not arguing for the sake of arguing, I know what it was designed to do and what the behaviors are. I've worked with enough devices to know what's normal and what's not. Heck, even Apple has published documents that state the same thing I'm telling you, but you refuse to listen. What's worse is that a lot of you on these forums are giving out incorrect info that directly contradicts manufacturer's whitepapers.

OK ya you're wrong. When you wake the device and it's displaying a Cellular data symbol it was connected to a cellular data network plain & simple. When on a wi-fi network the iDevice should stay on that network until the signal degrades to the point of dropping the signal and switching to a stronger wi-fi signal or cellular data signal.

No I'm not wrong. When the device is in Sleep mode AND NOT PLUGGED IN, it'll drop off WIFI and back to 3G or whatever other cellular signal you're connected to. It's like this by design.

Correct, as stated already earlier in this thread.

Yes, you can manually request a sync from the iDevice or iTunes when Wi-Fi is active and iTunes/Bonjour may even be smart enough to locate the device when it's not active on Wi-Fi but available. But when not plugged in and sleeping Wi-Fi is inactive by design.--My GalleryFormerly Nezmo

My iphone 5 doesn't have a problem connecting to wifi after waking back up but it does have a problem with my school's captive portal. Usually I have to reboot my phone after the network kicks me off for inactivity (30 minutes of idle, I think). It will connect but it wont bring up the CP page.

My iphone 5 doesn't have a problem connecting to wifi after waking back up but it does have a problem with my school's captive portal. Usually I have to reboot my phone after the network kicks me off for inactivity (30 minutes of idle, I think). It will connect but it wont bring up the CP page.

My Evo never had issues with that.

I've seen similar issues with both hotel WIFIs as well as even private networks. A couple of things to try would be to go into WIFI and turn it off and back on. If that doesn't work, then go into WIFI and see if the actual network you want to be connected to is listed. If so, just tap it once to force a connection. If you get an error that it won't connect, then that's usually a firmware issue with whatever WIFI network hardware they're using. If the behavior is as such, maybe try to report it to your school's IT dept... find someone higher up than the regular tech guys if they seem unconcerned with your issue. They certainly won't be at the level that is required to apply such fixes anyway if it's a firmware problem with the equipment. Good luck and I hope you can get it fixed soon.... for yourself and I'm sure others at well.

It sounds like to me that Apple has worked out a way that the data service providers can increase your usage of the cellular network to increase your bill which undoubtedly has resulted in kickbacks. It is pretty crafty and I'm sure most people won't even notice. What really blows my mind is that they have people saying that it is to save battery life. I can't imagine that the amount of supposed saved battery life is even measurable. Reeks of a scam to me.